It is well known in the prior art to use log delimbers, processors, single grip harvesters and other log processing machines (hereinafter collectively referred to as processors) for example in the form of attachments for mounting to the distal end of the boom and stick of an excavator for the delimbing and processing of felled trees. Conventionally, the delimber attachment picks up one end of a felled tree or, when the trees are of smaller diameter, gathers the ends of a plurality of trees so as to place the end of the tree or trees between a pair of drive wheels mounted on opposite sides of the tree or trees. A pair of grappling arms hold the ends of the trees between the drive wheels and up against an elongate supporting frame to which are mounted the grappling arms and the drive wheels. With the grappling arms hugging the trees up against the support frame so as to dispose the ends of the trees between the drive wheels, the drive wheels are actuated so as to snugly frictionally engage opposite sides of the tree or trees therebetween and driven so as to run the tree or trees longitudinally along their length thereby causing the arms to strip the branches. The tree or trees so longitudinally driven by the pair of wheels may be subject to repeated passes through the arms by the reversing of the drive direction of the wheels so as to produce a reciprocating stroke of the tree trunks until the operator is satisfied with the result. The frame may also support a remotely actuable saw for cutting the trunks, once delimbed, into lengths.
In the prior art, the drive wheels may conventionally be for example either entirely rigid wheels whose outer surface are covered by spikes or other grip enhancing means, or may be rubber sheathed wheels employing chain wrapped around the inner and outer surfaces of the wheel. The chains are wrapped to produce a torus-like protective cover around the rubber and so that the wrapped strand of chain enhances the grip of the rubber drive wheel engaging the tree trunks being held in the delimber. It is this latter type of wheel which is the subject of the improvements according to the present invention.
The conventional rubber wheels used in conjunction with a wrapped chain are one piece wheels. Consequently, as the chain during use wears and stretches, the chain becomes more loosely wrapped around the wheel and consequently increases the rate of erosion of the rubber outer liner on the wheel beyond that normally encountered when the chain is tight, resulting in the premature wear of the rubber outer liner and a shortened useful life of the rubber outer liner before the entire wheel must be replaced and the worn wheels sent for expensive refurbishing. Of course, operators may, and should, periodically tighten the chain wrap to take up the slack in the chain due to wear and stretching so as to extend the useful life of the rubber wheel. However, in reality, because this is quite a time consuming exercise involving having to remove the entire wheel from the delimber and thereby causing significant down time of the equipment, operators often will not perform such periodic tightening of the chain. Consequently, it is one object of the present invention to assist operators in more simply and quickly tightening lengths of chain mounted onto the modular rubber drive wheel of the present invention and to provide for ease of interchangeability of parts of the drive wheel which are subject to wear.